The invention relates to diaphragm spring friction clutches and in particular to the provision of secondary drives from such friction clutches.
A typical diaphragm spring clutch comprises a cover member, a pressure plate mounted with respect to the cover member and a diaphragm spring having an outer annular belville portion and inwardly directed fingers disposed between the cover member and the pressure plate. In use the clutch is mounted on a flywheel and a driven plate is interposed between the flywheel and the pressure plate. The diaphragm spring urges the pressure plate into frictional engagement with the driven plate and the driven plate into frictional engagement with the flywheel. In one now well established kind of friction clutch, as described in U.K. Patent Specification No. 1 347 485, the diaphragm spring is located with respect to the cover member by tabs passing through mounting apertures at the roots of the fingers of the diaphragm spring and bent over the hold the diaphragm spring in position.
There is often a requirement, particularly but not exclusively in connection with agricultural and utility vehicles, to provide a secondary drive from the clutch, in addition to the main drive through the driven plate. The secondary drive is normally connected to a hollow shaft, concentric with the driven shaft from the primary drive. It is desirable to be able to connect the clutch cover to the secondary drive shaft by a secondary drive member without altering the design of the cover or other parts of the clutch. This simplifies the provision of a secondary drive for an existing design of clutch. Hitherto, there has been no convenient way of providing a secondary drive from the kind of clutch described in U.K. Patent Specification No. 1 347 485 and an objective of the present invention is to provide such a secondary drive.